Variable condenser plate mounting



April 1939- H. NELSON 7 2,155,201

VARIABLE CONDEN SER PLATE MOUNTING Original Filed Feb. 24. 1936 a; 2%) ma Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE Hugo Nelson, Chicago, Ill., assignor to Reliance Die & Stamping Company, Chicago, Ill., a corporation of Illinois Application February 24, 1936, Serial No. 65,365 Renewed September 21, 1938 4 Claims.

This invention relates broadly to plate mountings for variable condensers and more particularly for the stator plates of a variable condenser.

Among other objects, the invention aims to provide an improved and simplified mounting means which permits easier assembly of the parts while at the same time improving the security of assembly whereby large-volume production may be enhanced and the cost per unit decreased.

m An important object in the invention is to provide mounting means of this type which permits selective adjustability of the stator plates with respect to the condenser frame.

A further object of the invention is to provide '5 unitary mounting means for both of the stator plates and a trimmer plate associated with each group of stator plates and whereby the trimmer plate may be readily assembled or disassembled with ease and with a minimum of disturbance of the stator plates.

Other objects and advantages will be apparent from the following description taken together with the accompanying drawing showing an illustrative embodiment of the invention in which- 25 Figure 1 is a reduced view of a complete condenser with which the present invention is associated, parts of the condenser frame being shown in section for clearness of description and being a section taken on the line l-l of Fig. 3;

3 Fig. 2 is an enlarged fragmentary view of the right-hand portion of Fig. l and being a section taken on the line 22 of Fig. 3;

Fig. 3 is a side elevational view of the structure of Fig. 2;

Fig. 4 is abottom view of the structure of Fig. 2;

Fig. 5 is an exploded view of parts in perspective; and

Fig. 6 is a further enlarged perspective view of still another part.

In the illustrative embodiment shown in detail in the drawing, Fig. 1 shows in general, a somewhat conventional variable condenser of the compact type commonly used in the majority of radios now produced. The condenser frame may include the metallic end plate It. and longitudinally extending frame members such as the cylindrical metallic rods H and metallic bars 12, to which the end plate secured, as is also a partition plate iii. The usual rotatable shaft l3, g, journaled in the end plate ii), has keyed thereto a plurality of rotor plates it which are adapted to be interleaved in selective mcre-or-less lapping relation with the parallel. spaced-apart stator plates l5. As best shown in Figs. 3 and i, a group 55 of stator plates l5 are assembled together in fixed spatial relation and carried between the end plate I0 and the metallic partition plate I6. The condenser parts between the end plate l0 and partition plate l6 may constitute one unit or section of a socalled tandem-drive gang condenser, other similar units being carried by the same frame.

In accordance with the present invention the stator plates of such a group are rigidly fastened in predetermined spatial relation to the metallic tie bar I1, any suitable means being employed for securing the plates to the tie bar, for example by providing regularly spaced apart parallel apertures l8, H! in opposite sides of the tie bar. through which are passed and riveted nibs .and 2| respectively, formed integrally on the stator plates to register with the apertures l8, l9 respectively. It will be understood, as shown in Fig. 1, that there is a tie bar I! at each side of the group of stator plates so that a group of these plates may be moved as a unit in and out of the condenser frame during an assembly operation with the normal position of the stator plates perpendicular to the frame members H and I2 and the tie bars I! at each side of the stator plates transverse to the stator plates and thus parallel to these frame members.

Since it is desirable that the stator plates be insulated from the metallic frame, each of the frame members l2 has riveted thereto the support 22 of any suitable insulating material such as synthetic resin, as by the rivets 23 passing through holes 24 in the support 22. As best shown in Fig. 5, the support 22 is advantageously of triangular shape having a cutout part 25 within its perimeter and the holes 24 and another hole 26 triangularly arranged about the cutout part 25, the hole 26 being in an upwardly extending portion 21 of the support to which the stator plates are attached as next described.

The hole 26 in the insulating support 22 is adapted to have passed therethrough a holding member such as the screw 28 shown in exaggerated perspective in Fig. 6 having a threaded shank 29, an intermediate enlarged shank portion 30, and a still further enlarged head 3|. In accordance with the present invention the screw 28 may be passed through the hole 26 in the support prior to engagement with the stator plate tie bar 11. For this purpose, the tie bar is provided with a slot having a relatively wide portion 32 and a relatively narrow portion 33. In this instance the tie bar I! is of angular formation and the relatively wide slot portion 32 is located in one angular portion 34 and the relatively narrow slot portion 33 in another angular portion 35, the slot portions however being in communication. The relatively narrow slot portion 33 is vertically disposed and the tie bar portion in which this slot portion is formed is channeled transversely perpendicularly to the condenser plates and therefore parallel with the frame member I2, thus providing downwardly facing shoulders 36 at the upper end of the slot 33. Thus with the screw 28 conveniently disposed in the hole 26 of the support 22 with the head 35 of the screw upon the inner side of the support and the shank 29 passing therethrough outwardly of the frame, the head of the screw by being moved slightly away from the support but without removing the screw therefrom, may be slipped through the relatively wide slot portion 32 so that the shank of the screw is disposed in the relatively narrow slot portion 33, and particularly with the intermediate shank portion 30 of the screw in the slot portion 33. This intermediate shank portion is desirably of non-circular crsssection, being here shown square, for a purpose presently pointed out. The slot portion 33 is longer longitudinally of the frame members 12 than the width of the shank of the screw, to provide play in the slot so that the condenser plates l may have a selective relative adjustment, longitudinally of the frame, with respect to the screw 28 and the support 22. To ensure that the head of the screw will engage the tie bar in all selected adjusted positions, the head 3i of the screw is shown elongated to rest in the channel part 32 of the tie bar with its greater length lengthwise of the channel, the shoulders 35 of the tie bar resting as by gravity on the longer side of the head 3|. The shoulders 35 thus provide an abutment parallel with the screw head which prevents relative rotation of the tie bar and screw when the screw is in operative position in the slot. Thus it will be understood that a group of stator plates may he slipped on and oil the support 22 without removing the screw 28 from the latter. When the tie bar ll has been engaged with the screw as just described, completion of the assembly and a tight rigid relationship is readily obtained by means of the clamping member represented by the nut Bl which is threaded onto the shank 29 of the screw. To further ensure this rigid connection, the hole Ed in the support 22 is desirably of non-circular shape, being here shown square, to snugly receive the intermediate enlarged square portion 35 of the "rank of the screw and thus prevent relative rotation of the screw and support when the parts are in clamped assembly.

In order to make an electrical connection with the stator plates, the nut El also desirably clamps to the screw 28 the usual metallic connector lug 38 which is perforated as at 39 for having a wire passed therethrough. A lip 40 at the lower end of the connector lug 38 may engage the up per margin of the cut-out portion 25 of the insulating support 28 to prevent turning of the connector lug on the screw.

It is frequently desirable to have a small adjustable trimmer plate carried adjacent each of the groups of stator plates, for adjustmet at the factory of the minimum and maximum capacities of the condenser, and further in accordance with the present invention, such a device may be readily attached to the condenser along with the stator plates themselves by the unitary holding member represented by the screw 28. Thus the metallic trimmer plate 4| has a hole 42 therein through which the shank 29 of the screw 28 may be readily passed and the trimmer plateclamped to the screw by a nut 43, in this instance in addition to the nut 31, the trimmer plate being here shown clamped between the two nuts.

It will be understood that the trimmer plate is in electrical connection with the stator plates but is insulated from the condenser frame as are the stator plates, and for this purpose the lower end 44 of the trimmer plate is spaced from the frame portion i2 by being bent away therefrom. An adjustment set-screw passes through an enlarged hole 46 in the trimmer plate and is insulated from the trimmer plate by an insulating washer 4'! disposed between the head of the screw 45 and the trimmer plate and also by the fact that the hole 46 is of larger diameter than the shank of the screw 45. By screwing the screw 45 into and out of the threaded hole 48 in the frame member l2 against the resilience of the trimmer plate portion 44, this portion may be moved nearer to or further from the frame member [2 to effect slight chan es in capacity of the condenser as a whole. The cut-out portion 25 of the support 22 further serves to admit the inner end of the screw 45 without interference therewith. To further insure insulation of the trimmer plate from the frame, a small mica sheet may be disposed between these parts and also carried by the screw 15, ears 5!) on the trimmer plate abutting the upper edge 5i of the mica sheet 49 and preventing rotation thereof.

Thus is disclosed a unitary mounting means for ready assembly of either or both of the condenser plates and trimmer plate with ease and rapidity while at the same time permitting ready adjustment of the parts with a minimum of disturbance of any other part.

It will be apparent that the invention is not limited to the details of construction shown for purposes of illustration. Furthermore, it is not essential that all features of the invention be used conjointly, as various combinations and sub-combinations may be advantageously employed.

What is claimed is:

1. In mounting means for the stator plates of a variable condenser, the combination with a frame member of insulating material, of a tie bar rigidly connecting a plurality of the plates in spaced parallel relation transversely to the frame member, said tie bar having a portion spaced from the plates and parallel with the frame member, a slot in said portion, a screw passing outwardly of the slot and engaging the frame member, said screw having a head and shank, an aperture in the frame member snugly receiving the shank, said aperture being of noncircular formation and the screw shank having an intermediate portion adjacent its head matingly received in said aperture to prevent relative rotation of the screw and frame member, said slot being elongated transversely of the plates whereby the tie car may be adjusted with respect to the screw and frame member and the head of the screw being longer than the elongation of said slot, an abutment on the tie bar parallel with said screw head and preventing relative rotation of the tie bar and screw, and a nut on the exterior of the frame member securing said screw thereto.

2. In mounting means for the stator plates of a variable condenser, the combination with a frame member of insulating material, of a tie bar rigidly connecting a plurality of the plates in spaced parallel relation transversely to the frame member, said tie bar having a portion spaced from the plates and parallel with the frame member, a slot in said portion, a screw passing outwardly of the slot and engaging the frame member, said screw having a head and shank, an aperture in the frame member snugly receiving the shank, said aperture being of noncircular formation and the screw shank having an intermediate portion adjacent its head matingly received in said aperture to prevent relative rotation of the screw and frame member, said slot being elongated transversely of the plates whereby the tie bar may be adjusted with respect to the screw and frame member and the head of the screw being longer than the elongation of said slot, and a nut on the exterior of the frame member securing said screw thereto.

3. In mounting means for the stator plates of a variable condenser, the combination with a frame member, of a tie bar rigidly connecting a plurality of the plates in spaced parallel relation transversely to the frame member, said tie bar having a portion spaced from the plates and parallel with the frame member, a slot in said portion, a single screw passing outwardly of the slot and engaging the frame member, said screw having a head and shank, an aperture in the frame member receiving the shank, said slot being elongated transversely of the plates whereby the tie bar may be adjusted with respect to the screw and frame member and the head of the screw being longer than the elongation of said slot, a nut on the'exterior of the frame member securing said screw thereto, and. means preventing relative rotation of the tie bar and screw.

4. In mounting means for the stator plates of a variable condenser, the combination with a frame member, of a tie bar rigidly connecting a plurality of the plates in spaced parallel relation transversely to the frame member, said tie bar having a portion spaced from the plates and parallel with the frame member, a slot in said portion, a screw passing outwardly of the slot and engaging the frame member, said screw having a head and shank, an aperture in the frame member snugly receiving the shank, said aperture being of non-circular formation and the screw shank having'an intermediate portion adjacent its head matingly received in said aperture to prevent relative rotation of the screw and frame member, and a nut on the exterior of the frame member securing said screw thereto.

HUGO NELSON. 

